^P  U.  S.  DEPARTMENT  OF  AGRICULTURE, 

3  BUREAU  OF  ANIMAL  INDUSTRY.— Brnj-TiN  No.  89. 

_    I  A.   D.  MKLVIN,  CHIEF  OF  BUREAU. 


INVESTIGATIONS    IN   THE  MANUFACTURE 
AND   STORAGE   OF   BUTTER. 


II -PREVENTING  MOLDS  IN  BUTTER  TUBS. 


BY 


1..   A.   ROGERS. 

fiaftt •;/<'/«.;'/«//  C'/ti-wis/,  Dairy  Division, 
of  Animal  Industry. 


WASHINC,  |oN: 

.  I     PR  IN  ;  I  K.r 


ORGANIZATION  OF  THE  BUREAU  OF  ANIMAL  INDUSTRY. 


Chief:  A.  D.  MELVIN. 

Assistant  Chief:  A.  M.  FAKRINGTON. 

Ctdtf&terJc:  K.  B.JONES. 

Dairy  Diriinon:  ED.  H.  WEBSTER,  chief;  CLARENCE  B.  LANE,  assistant  chief. 

IiiKjtfdion   Dmsion:  RICE   P.  STEDDOM,   chief;  U.  G.   HOUCK,   associate   chief;  MORRIS 

WOODEN,  assistant  chief. 

Quarantine  Division:  RICHARD  W.  HICKMAN,  chief. 
Animal  Husbandman:  GEORGE  M.  ROMMEL. 
Editor:  JAMES  M.  PICKENS. 
.lr/;.s/.-  W,  S.  D.  HAINES. 
Librarian:  BEATRICE  C.  OBERLY. 

LABORATORIES. 

Biochemic  Division:  MARION  DORSET,  chief. 
Pathological  Diiision:  JOHN  R.  MOHLER,  chief. 
Zoological  Division:  BRAYTON  H.  RANSOM,  chief. 

EXPERIMENT    STATION. 

E.  C.  SCHROEDER,  superintendent;  W.  E.  COTTON,  assistant. 

MEAT   INSPECTION. 

Inspectors  in  charge. 


Arkansas  City,   Kans. — Dr.    R.    W.    Tuck,  care 
Hemieberry  &  Co. 

Austin,  Minn.— Dr.  M.  O.  Anderson,  care  George 
A.  Ilormel  &  Co. 

Baltimore,  Md.— Dr.  H.  A.  Hedrick,  215  St.  Paul 
street. 

Bloomington,  111.— Dr.  Frederick  Braginton,  care 
Continental  Packing  Company. 

Boston,  Mass.— Dr.  J.  F.  Ryder.  141  Milk  street. 

Bright  wood,    Mass. — Dr.    W.    J.    Murphy,    care 
Springfield  Provision  Company. 

Buifalo,  N.  Y.— Dr.  B.  P.  Wende,  Live  Stock  Ex- 
change Building,  East  Buffalo. 

Cedar  Kapids,  Iowa.— Dr.  T.  A.  Shipley,  care  T.  M. 
Sinclair  &.  Co. 

Chicago,  111.— Dr.  S.  E.  Bennett,  room  316  Ex- 
change Building,  Union  Stock  Yards. 

Cincinnati,  Ohio. — Dr.  A.  G.  G.  Richardson,  care 
Union  Stock  Yards.  , 

and,  Ohio.— Dr.  E.  P.  Schaflter,  care  Cleve- 
land Provision  Company. 

Davenport,  Iowa.— Dr.  E.  L.  Bertram. care  Henry 
Kohrs  Packing  Company. 

Denver,  Colo.— Dr.  W.  E.  Howe,  care  Western 
Packing  Company. 

Des  Moines,  Iowa. — Dr.  Chester  Miller,  care  The 
Agar  Packing  Company. 

Detroit,  Mich. — Dr.  L.  K.  Green,  care  Hammond, 
Standish  &  Co. 

Eau  Claire,  Wis.— Dr.  G.  W.  Butler,  care  Drum- 
inond  Brothers.  , 

Fort  Worth,  Tex.— Dr.  A.  II.  Wallace,  care  Swift 
&Co. 

Ilutchinson,    Kans.— Dr.    ,T.    E.    Bluc'.cwell,  care 
Hutchinson  Packing  Company. 

Indianapolis,  Ind.— Dr.  N.  C.  Sorensen,  care  Kin- 
gan  &  Co. 

Jersey  City,  N.  J.— Dr.  Julius  Huelsen,  care  The 
Jersey  City  Stock  Yard  Co:npany. 

Kansas  City,  Kans.— Dr.  1,.  R.  Baker,  room  338 
Live  Stock  Exchange. 

Lafayette,  Ind.— Dr.  J.  E.  Cloud,  care  Kern  Pack- 
ing Company. 

Los  Angeles,  Cal. — Dr.  A.  E.  Rishel,  care  Cudahy 
Packing  Company. 

Louisville,  Ky.— Dr.  II.  II.  George,  507  Johnsoji 
street. 

Mankato,  Minn.— Dr.  H.  H.  Dell,  care  Macbeth  & 
Gardner. 

Marshalltown,Iowa.— Dr.  J.  O.  F.  Price,  care  Brit- 
tain  &  Co. 

Mason  City,  Iowa.— Dr.  Robert  Jay ,  care  Jacob  E. 
Decker  &  Sons. 


Milwaukee,  AVis. — Dr.   A.   E.   Behnke,  room  432 

Federal  Building. 

Nashville,  Tenn.— Dr.  W.  B.  Lincoln,  care  Tennes- 
see Packing  and  Provision  Company. 
National  Stock  Yards,  111.— Dr.  J.  B.  Clancy. 
Nebraska  City,  Nebr.— Dr.   W.   II.   Gibbs,  care 

Morton-Gregson  Company. 
Newark,  N.  J.— Dr.  A.  F.  Martins,  care  Swift  & 

Co.,  Harrison  Station. 
New  Haven,  Conn. — Dr.  Albert  Long,  care  Spcrry 

<t  Barnes. 
New  York,  N.  Y.— Dr.  H.  N.  Waller,  109  West 

Forty-second-street. 
Oklahoma  City,  Okla.— Dr.  Raymond  Johnson, 

P.  O.  box  1285. 
Ottumwa,  Iowa. — Dr.  Joshua  Miller,  care.  John 

Morrell  &  Co. 
Philadelphia,  Pa.— Dr.  C.  A.  Schaufler,  134  South 

Second  street. 
Pittsburg,  Pa.— Dr.  F.W.  Ainsworth,  Union  Stock 

Yards. 
Portland,  Oreg. — Dr.  Clarence  Loveberry,  room 

402  Custom-House  (new). 
Quincy,    111.— Dr.    J.    S.    Kelly,   care   Blomer   & 

Michael  Co. 
St.  Louis,  Mo.— Dr.  J.J.  Brougham, care  Missouri 

Stock  Yards  Company. 
San  Diego,  Cal.— Dr.  Robert  Darlirg,  care  Charles 

S.  Hardy. 
San  Francisco,  Cal. — Dr.  George  S.  Baker,  care 

Western  Meat  Company. 
Seattle,  Wash.— Dr.  O.  B~.  Hess,  care  Frye-Bruhn 

Company. 
Sioux  City,  Iowa.— Dr.  G.  A.  Johnson,  Exchange 

Building. 
Sioux  Falls,  S.  Dak.— Dr.  Herman  Busman,  care 

Sioux  Falls  Packing  Company.  i 

South  Omaha,  Nebr.— Dr.  Don  C.  Aver,   Post- 

Office  building. 

South  St.  Joseph,  Mo.— Dr.  George  Ditewig. 
South  St.  Paul,  Minn.— Dr.  F.  D.  Ketchum. 
Tacoma,  Wash. — Dr.  E.  C.  Joss,  care  Carstens 

Packing  Company. 
Topeka,  Kans.— Dr.  F.  L.  De  Wolf,  care  Charles 

Wolff  Packing  Company. 
Waterloo,  Iowa.— Dr.  T.  W.  Scott,  care  the  Rath 

Packing  Company. 
Wichita,  Kans.— Dr.  W.  N.  Neil,  care  John  Cudahy 

Company. 
Worcester,  Mass.— Dr.  E.  P.  Dowd,  care  White, 

Pevey  &  Dexter  Co. 


(Concluded  on  p.  3  of  cover.) 


U.  S.  D'EPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.— BULLETIN  No.  89. 
A.  D.  MELVIN,  CHIEF  OF  BUREAU. 


INVESTIGATIONS   IN   THE  MANUFACTURE 
AND   STORAGE   OF  BUTTER. 


II.-PREVENTING  MOLDS  IN  BUTTER  TUBS, 


BY 


L   A.   ROGERS. 

Bacteriological  Chemist,  Dairy  Division, 
Bureau  of  Animal  ludiistrv. 


WASHINGTON: 
GOVERNMENT    PRINTING   <»FHCE. 

1906. 


ORGANIZATION  OF  THE  DAIRY  DIVISION. 


ADMINISTRATION . 

Chief:  Ed.  H.  Webster. 
Assistant  Chief:  C.  B.  Lane. 
Assistant:  Wm.  Hart  Dexter. 

SCIENTIFIC   STAFF. 

Butter  investigations:  Chief,  in  charge;  C.  E.  Gray,  chemist  and  experimental  maker; 
C.  W.  Fryhofer,  assistant;  E.  A.  McDonald,  W.  S.  Smarzo,  W.  J.  Credicott,  market 
inspectors. 

Market  milk  investigations:  Assistant  Chief,  in  charge;  R.  H.Shaw,  chemist;  George  M. 
Whitaker,  assistant.  • 

Cheese  investigations:  C.  F.  Doane,  in  charge.  American  varieties:  John  L.  Sammis,  chem- 
ist; Jay  W.  Moore,  expert  maker.  European  varieties:  Charles  Thorn,  mycologist; 
Arthur  W.  Dox,  chemist;  T.  W.  Tssajeff,  expert  maker. 

Southern  dairy  investigations:  B.  H.  Rawl,  in  charge;  H.  N.  Slater,  Duncan  Stuart,  J.  A. 
Conovei,  S.  E.  Barnes,  J.  W.  Ridgeway,  J.  E.  Dorman,  assistants. 

Building  and  management  investigations:   B.  D.  White,  in  charge;  G.  H.  Parks,  architect. 

Dairy  laboratories:  C.  E.  Gray,  chemist;  L.  A.  Rogers,  bacteriological  chemist. 

INSPECTION    STAFF. 

Renovated  butter  factories:  M.W.Lang,  510  Northwestern  ^Building,  Chicago,  111.,  in  charge. 

Renovated  butter  markets:  Levi  Wells,  Laceyville,  Pa.,  in  charge. 

Inspectors:  Robert  McAdam,  510  Northwestern  Building,  Chicago,  111.;  George  M.  Whit- 
aker, Washington,  D.  C  ;  E.  A.  McDonald,  Seattle,  Wash. 

Deputy  inspectors:  S.  B.  Willis,  Boston,  Mass.;  R.  A.  McBride,  J.  H.  Barrett,  6  Harrison 
street,  New  York,  N.  Y. 

2 


LETTER  OF  TRANS/YIITTAL. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY, 

Washington,  D.  C.,  July  14,  1906. 

SIR:  I  have  the  honor  to  transmit  herewith,  and  to  recommend 
for  publication  as  a  bulletin  of  this  Bureau,  a  manuscript  entitled 
"Preventing  Molds  in  Butter  Tubs,"  by  L.  A.  Rogers,  bacteriolog- 
ical chemist  in  the  Dairy  Division.     This  paper  is  the  second  in  a 
series  on  Investigations  in  the  Manufacture  and  Storage  of  Butter. 
Acknowledgment  is  made  of  courtesies  and  facilities  extended  by 
the  managers  of  the  creameries  at  Eagle  Lake,  Minn.,  and  Bloomer, 
Wis.,  and  by  the  Fox  River  Butter  Company  in  connection  with  the 
experiments  reported  in  this  bulletin. 
Respectfully, 

A.  D.  MELVIN, 

Chief  of  Bureau. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 


CONTENTS. 


Page 

Conditioas  favoring  the  growth  of  molds 7 

Propagat  ion  of  molds 8 

Growth  of  molds  in  butter  tubs 8 

Prevention  of  molds  in  tubs. . . .  * 9 

Testing  and  comparison  of  methods 9 

Method  of  applying  paraffin 11 

Cost  of  paraffining  tubs 12 

Summary 13 


ILLUSTRATION. 


FIG.  1.  Apparatus  for  paraffining  tubs. 


PREVENTING  MOLDS  IN  BUTTER  TUBS. 


There  is  probably  no  one  trouble  that  causes  butter  dealers  so 
much  annoyance  as  the  growth  of  molds  on  the  inside  of  butter  tubs. 
This  is  a  trouble  that  is  not  confined  to  any  one  geographical  sec- 
tion or  to  any  one  type  of  factory.  It  may  be  only  an  occasional 
outbreak  even  in  the  best  managed  factory,  or  it  may  become  a 
chronic  condition  which  the  buttermaker  is  unable  to  control. 

Before  discussing  the  methods  of  preventing  the  growth  of  molds 
in  tubs  it  will  be  well  to  consider  briefly  some  of  the  characteristics 
of  these  tiny  plants  and  the  conditions  under  which  they  grow. 

CONDITIONS    FAVORING   THE    GROWTH    OF    MOLDS. 

Molds  are  plants  and  obey  certain  fixed  laws  governing  the  group 
of  which  they  are  a  type.  They  differ  from  the  common  plants 
with  which  we  are  familiar  in  everyday  life  in  that  they  possess  none 
of  the  green  coloring  matter  by  which  the  higher  plants  utilize  the 
energy  of  the  sun's  rays  in  building  up  their  tissues.  Hence  they  live 
as  well  or  better  in  darkness  than  in  light,  but  are  limited  for  their 
food  supply  to  materials  that  have  been  prepared  for  them  by  ani- 
mals or  by  other  plants.  Almost  any  animal  or  vegetable  matter 
serves  them  for  food.  We  find  them  growing  on  bread,  meat,  bones, 
damp  wood,  leather,  and  many  other  things.  Sugars  and  many  of 
the  acids  may  be  used,  and  we  frequently  find  a  luxuriant  growth 
of  mold  on  foods  containing  sufficient  sugar  or  acid  to  prevent  the 
growth  of  bacteria  or  yeasts. 

A  certain  amount  of  moisture  is  necessary  for  the  growth  of  molds. 
Growth  will  not  occur  on  the  surface  of  wood  or  leather  unless  it  is 
allowed  to  remain  in  a  damp  place. 

Oxygen  is  necessary  to  the  development  of  all  living  things. 
Some  of  the  bacteria  which  live  only  under  conditions  that  exclude 
air  completely  seem  to  be  an  exception  to  this  rule.  Those  forms, 
however,  obtain  their  oxygen  from  certain  constituents  of  their 
food.  The  molds  are  unable  to  do  this,  and,  like  the  higher  plants, 
live  only  where  there  is  at  least  a  limited  supply  of  air. 

While  a  certain  amount  of  heat  is  essential  to  the  growth  of  molds, 
there  is  a  wide  range  of  temperature  under  which  growth  is  possible. 
Many  of  the  molds  grow  most  rapidly  at  blood  heat,  but  continue 
to  grow  slowly  at  temperatures  near  the  freezing  point.  Other 
varieties  find  the  most  favorable  conditions  at  lower  temperatures 
and  grow  with  comparative  rapidity  in  ordinary  refrigerators. 


8  MANUFACTURE    AND    STORAGE    OF    BUTTER. 

PROPAGATION    OF    MOLDS. 

Molds  reproduce  themselves  by  yeastlike  buds  or  by  spores  which 
correspond  more  closely  to  the  seeds  of  higher  plants.  The  buds, 
or  conidia,  as  they  are  called,  are  easily  destroyed;  the  spores,  on 
the  other  hand,  on  account  of  their  peculiar  structure,  resist  for 
some  time  conditions  that  would  destroy  the  mold  itself  almost 
instantly.  Spores  may  be  dried  for  years  and  yet  under  favorable 
conditions  they  will  germinate  and  in  a  surprisingly  short  time  pro- 
duce a  mycelium  bearing  millions  of  spores.  They  are  able  to  endure 
much  more  heat  than  the  mold  itself,  but  are  destroyed  by  a  short 
exposure  to  boiling  water.  In  a  dry  condition  they  are  much  more 
resistant. 

Short  exposures  to  disinfectants  destroy  the  spores,  but  molds 
readily  adapt  themselves  to  unfavorable  conditions  and  are  fre- 
quently found  growing  in  the  presence  of  antiseptic  sufficient  to 
inhibit  completely  the  growth  of  bacteria. 

These  spores  and  conidia  are  formed  in  enormous  numbers,  and 
on  account  of  their  minute  size  and  exceedingly  light  weight  are 
carried  about  by  every  movement  of  air.  It  is  therefore  almost 
impossible  in  practice  to  prevent  entirely  infection  by  molds.  The 
most  efficient  means  of  holding  them  in  check  is  to  provide  condi- 
tions unfavorable  to  their  growth.  This  may  be  done  by  depriving 
them  of  one  or  more  of  the  factors — food,  air,  moisture,  or  heat — 
which  have  been  mentioned  as  essential  to  their  growth. 

GROWTH    OF    MOLDS    IN    BUTTER    TUBS. 

Tubs  can  not  be  made  or  transported  without  contamination, 
but  if  they  are  reasonably  dry  the  spores  will  not  germinate.  If, 
however,  the  wood  is  not  well  seasoned,  or  if  the  finished  tubs  are 
held  at  the  factory  in  a  damp  storeroom,  the  few  spores  grow  and 
in  a  short  time  the  surface  of  the  wood  is  covered  with  a  growth  of 
mold.  The  tub  may  come  from  the  factory  in  good  condition  and 
be  stored  in  the  creamery  in  a  damp  place.  This  may  be  in  the  ice 
house  or  next  to  the  damp  wall  of  the  ice  house  or  refrigerator.  The 
growth  of  .mold  ma}7  not  be  noticeable  without  close  examination. 
When  the  tubs  are  filled  with  butter,  the  air  is  excluded  and  the 
molds  are  unable  to  grow,  but  after  a  few  days  the  evaporation  of 
water  causes  the  butter  to  shrink  away  from  the  tub,  leaving  a  very 
small  air  space.  Favorable  conditions  of  food,  moisture,  and  air 
are  thus  provided,  and  if  the  temperature  is  not  too  low  growth  will 
begin  again. 

It  is  a  common  belief  that  moldy  refrigerators  are  responsible  for 
mold  in  butter  tubs,  but  from  the  nature  of  the  package  it  is  very 
improbable  that  the  inside  of  the  tub  could  become  contaminated 
after  it  is  filled.  Temperature  and  moisture  conditions  that  would 


PREVENTING    MOLDS    IN    BUTTER    TUBS.  9 

allow  molds  to  grow  on  the  wall  of  a  refrigerator  would  favor  the 
growth  of  molds  on  the  inside  of  the  tub,  but  the  infection  must  come 
before  the  tub  is  put  in  the  refrigerator.  The  growth  of  molds  on 
the  walls  could  be  prevented  by  occasionally  wiping  the  wall  with  a 
cloth  moistened  in  a  5  per  cent  glycerin  solution  of  corrosive  sub- 
limate. This  would  give  the  wall  a  thin,  sticky  coating  in  which  the 
floating  spores  would  be  held  and  destroyed. 

PREVENTION    OF    MOLDS    IN    TUBS. 

The  growth  of  molds  in  the  tub  may  be  prevented  more  or  less 
successfully  (1)  by  storing  the  tubs  in  a  dry  place,  (2)  by  storing 
the  butter  at  a  temperature  below  the  growth  point,  (3)  by  treating 
the  tubs  in  some  way  to  destroy  the  molds  and  their  spores,  or  (4) 
by  treating  the  tubs  with  some  preparation  on  which  molds  can  not 
grow. 

The  tubs  may  come  to  the  butter  maker  badly  infected,  or  he  may 
not  have  at  his  command  suitable  storage.  Few  creameries  have 
refrigerators  holding  a  temperature  low  enough  to  inhibit  the  growth 
of  molds  if  other  conditions  are  favorable.  The  butter  maker  is 
therefore  frequently  forced  to  resort  to  the  third  method. 

The  method  of  steaming  the  tubs  is  often  used  to  destroy  the  molds, 
but  this  has  not  been  very  effective.  It  is  difficult  to  heat  the  tub 
thoroughly  by  a  steam  jet,  and  the  sudden  swelling  of  the  tub  fre- 
quently breaks  the  hoops. 

Soaking  in  a  brine  containing  about  5  per  cent  of  formaldehyde  is 
a  method  sometimes  used,  and  one  commission  house  recommends 
that  the  tubs  be  boiled  in  brine  and  that  salt  be  rubbed  on  the  inside 
before  packing. 

A  few  of  the  larger  factories  have  recently  begun  coating  the  inside 
of  the  tubs  and  boxes  with  paraffin.  This  not  only  destroys  the  molds 
already  present  but  gives  a  surface  on  which  molds  will  not  grow. 

TESTING    AND    COMPARISON    OF    METHODS. 

Various  methods  were  tested  and  compared  by  the  writer  in  a 
creamery  which  had  had  serious  trouble  with  molds  all  through  the  pre- 
vious summer.  The  test  was  made  in  October,  when  the  temperature 
conditions  were  becoming  unfavorable  to  the  growth  of  molds.  The 
factory  was  a  new  one,  in  excellent  condition,  and  the  refrigerator, 
which  was  better  than  tin*  average,  was  free  from  molds.  However, 
the  tubs  were  stored  in  a  damp  room  on  the  north  side  of  the  cream- 
ery. The  practice  had  been  to  submerge  the  tubs  on  the  day  before 
they  were  used  in  a  saturated  brine  which  was  boiled  by  blowing 
steam  into  it,  and  to  allow  them  to  stand  in  the  warm  brine  over- 
night. Before  packing,  the  sides  of  the  tubs  were  coated  with  salt. 
This  had  not  proved  entirely  effective. 


10 


MANUFACTURE    AND   STORAGE    OF    BUTTER. 


For  the  experimental  work  thirty  20-pound  tubs  were  secured  and 
divided  into  six  lots  of  five  each.  Lot  I  was  old  tubs  from  various 
sources,  all  showing  more  or  less  mold,  while  some  were  very  moldy. 
Lots  II,  III,  IV,  and  V  were  new  tubs  received  direct  from  the  factory. 
Nearly  all  had  a  ring  of  mold  where  the  tubs  were  in  contact.  The 
tubs  of  Lot  II  were  purposely  wet  with  an  emulsion  of  moldy  cheese. 
Lot  VI  was  new  tubs  showing  no  mold. 

The  tubs  of  each  lot  were  numbered  from  1  to  5.  Tub  No.  1  in 
each  lot  was  soaked  overnight  in  cold  water  in  the  usual  way;  No. 
2  was  boiled  five  minutes  in  a  saturated  brine  and  left  in  the  brine 
overnight;  No.  3  was  soaked  overnight  in  a  brine  containing  9  per 
cent  of  commercial  formalin;  No.  4  was  coated  on  the  inside  with 
paraffin,  the  paraffin  being  applied  either  with  a  paint  brush  or  by 
pouring,  while  hot,  into  the  tub,  which  was  rotated  until  the  fluid 
had  flowed  over  the  entire  inside  surface;  No.  5  was  immersed  for  a 
few  seconds  in  a  bath  of  paraffin  at  250°  to  260°  F.  In  each  case 
the  liners  were  soaked  in  a  salt  solution. 

All  of  the  tubs  in  each  lot  were  filled  from  the  same  churning  and 
all  held  in  the  creamery  refrigerator  until  shipped.  The  first  lot  was 
held  ten  days,  the  second  nine,  the  third  eight,  the  fourth  seven,  the 
fifth  six,  and  the  last  lot  five  days  before  shipment.  The  butter  was 
shipped  in  a  refrigerator  car  and  was  received  at  Aurora,  111.,  six  days 
later  and  was  examined  the  following  day.  The  results  of  the  exam- 
ination are  given  in  the  following  table.  In  this  table  the  tubs  are 
described  as  moldy  only  when  there  was  an  evident  increase  of  the 
mold  originally  on  the  tub. 

Table  showing  results  of  experiments  in  treating  tubs  for  prevention  of  mold. 


Lot  No.    Tub  No. 


Treatment. 


Condition. 


1-    Untreated. 

Tub  and  liner  badly  molded 

2     Hot  brine.  . 

No  mold. 

I. 

3     Brine-formaldehyde    . 

Do. 

4     Coated  with  paraffin  

Do. 

5     Dipped  in  paraffin  

Do. 

1     Untreated.. 

Tub  and  liner  badly  molded. 

2     Hot  brine  

Do. 

II. 

3     Brine-fonnaldehvde 

No  mold 

4     Coated  with  paraffin 

Do. 

5     Dipped  in  paraffin 

Do. 

1     Untreated 

2     Hot  brine.  . 

Two  small  spots  of  mold  on  tub  and  liner 

III. 

3     Brine-fonnaldehvde 

No  mold. 

4     Coated  with  paraffin  

Do. 

5     Dipped  in  pa  raffin  

Do. 

1     Untreated.. 

Slightly  moldv. 

2     Hot  brine 

IV. 

3     Brine-formaldehyde 

Badly  molded. 

4     Coated  with  paraffin  .... 

No  mold. 

5     Dipped  in  paraffin  

Do. 

1     Untreated..   . 

Tub  and  liner  moldy. 

2     Hot  brine  

No  mold. 

V. 

3     Brine-formaldehyde 

Do 

4     Coated  with  paraffin. 

Do. 

5     Dipped  in  paraffin  

Do. 

1     Untreated.. 

Tub  and  liner  moldy. 

2     Hot  brine 

VI. 

3     Brine-formaldehyde  

Do. 

4     Coated  with  paraffin  

Do. 

5     Dipped  in  paraffin 

Do 

PREVENTING  MOLDS  IN  BUTTER  TUBS.  11 

It  will  be  seen  from  this  table  that  all  of  the  untreated  tubs  became 
moldy.  Of  the  six  tubs  treated  with  hot  brine  one  was  badly  molded, 
one  was  slightly  molded,  and  one  had  mold  on  the  outside.  Of  the 
six  tubs  soaked  in  the  brine-formaldehyde  mixture  one  was  badly 
molded.  None  of  the  tubs  coated  with  paraffin  showed  any  mold 
whatever,  and  the  same  was  true  of  those  dipped  in  paraffin. 

It  was  evident  that  each  of  these  methods  checked  the  growth  of 
mold  materially,  but  that  paraffining  was  much  more  efficient  than 
the  other  two  methods.  If  the  temperature  conditions  had  been 
more  favorable  to  the  molds  it  is  probable  that  these  differences 
would  have  been  greater. 

This  test,  so  far  as  it  goes,  indicates  that  the  formaldehyde  treat- 
ment is  more  efficient  than  the  hot-brine  method.  Salt  is  at  best  a 
weak  antiseptic.  Gripenberg0  has  shown  that  while  the  growth  of 
Penicillium,  the  mold  most  commonly  found  on  butter,  is  retarded 
by  5  per  cent  of  salt,  it  will  grow  slowly  in  10  and  even  20  per  cent 
solutions.  Twenty-five  per  cent  of  salt  completely  checked  its 
growth. 

To  treat  tubs  by  the  brine-formaldehyde  method  or  the  hot-brine 
method  a  vat  should  be  made  large  enough  to  hold  submerged  the 
tubs  used  in  one  day.  The  brine  may  be  boiled  by  blowing  steam 
into  it.  The  cost  of  either  of  these  two  methods  is  insignificant,  as 
the  bath  may  be  used  repeatedly.  The  objections  to  these  methods, 
in  addition  to  their  inefficiency,  would  probably  be  found  in  the  dis- 
coloring of  the  wood  and,  with  the  hot  brine,  in  the  excessive  weight 
and  swelling  of  the  tub. 

With  paraffining  not  only  are  the  molds  and  their  spores  already 
on  the  tub  prevented  from  growing,  but  the  wood  is  covered  with  a 
surface  from  which  molds  can  not  get  nourishment.  The  wood  is 
made  impervious  to  water,  and  the  space  between  the  tub  and  the 
liner  remains  filled  with  water,  so  that  the  molds  which  may  be  on 
the  liner  can  not  get  the  supply  of  air  necessary  to  their  growth.  The 
appearance  of  the  tub  is  unchanged  and  is  better  than  that  of  tubs 
soaked  in  brine  or  water. 

There  is  no  advantage  in  dipping  the  tubs  over  coating  the  inside, 
except  that  the  outside  will  not  become  moldy.  Dipping  has  the 
disadvantage  of  extra  cost  and  giving  the  outside  of  the  tub  a  surface 
which  can  not  be  marked  with  a  pencil. 

MKTIIOD    OF    APPLYING    PARAFFIN. 

The  paraffin  should  be  applied  in  such  a  way  that  it  will  give  an 
even,  thin  coating  which  fills  all  the  cracks  and  at  the  same  time  sinks 


o  GripenlMTg,  R.  Untereuchungen  QlxT  SrhirnmclhiUiung  Ix-i  I^Hp-rltultor.  Meddel 
Mustinlii  Inst.  Forsoksxtat  Mijiriafd,  Hi-Uin^ors,  IK99.  Review  in  Milch  fitting.  v.  28, 
No.  40,  pp.  026-028:  No.  41,  pp.  644-040.  Bremen,  1899. 


12 


MANUFACTURE    AND    STORAGE    OF    BUTTER. 


into  the  wood  sufficiently  to  prevent  the  coating  of  paraffin  from 
cracking  off.  The  application  may  be  made  with  a  brush,  but  it  may 
also  be  accomplished  by  pouring  a  small  amount  of  the  melted  paraffin 
into  the  tub  and  rotating  the  tub  until  the  paraffin  has  flowed  over 
the  entire  surface,  taking  care  that  it  does  not  run  down  the  outside 
of  the  tub.  By  the  latter  method  a  thinner,  evener  coating  may  be 
applied  than  by  using  a  brush. 

The  temperature  of  the  paraffin  is  important.  If  the  temperature 
is  too  low,  the  paraffin  will  cool  rapidly,  making  a  thick  uneven  coat- 
ing; if  the  paraffin  is  too  hot,  it  will  sink  into  the  wood  and  the  cracks 
will  not  be  closed  up.  If  the  paraffin  is  melted  by  holding  the 
receptacle  in  hot  water  or  steam,  it  will  be  found  advantageous  to 
heat  the  tub  over  a  steam  jet. 

The  paraffin  can  be  applied  most  rapidly  and  satisfactorily  by 
heating  it  to  250°  or  260°  F.  This  may  be  done  on  an  oil  stove,  but 
in  creameries  where  steam  is  always  available  it  will  be  better  to 
arrange  a  small  tank  with  a  steam  coil,  as  shown  in  figure  1. 


FIG.  1. — Apparatus  for  paraffining  tubs. 


By  connecting  the  coil  in  the  bottom  of  the  tank  with  the  boiler 
and  opening  the  waste  valve  only  enough  to  allow  the  escape  of  the 
water  of  condensation,  boiler  pressure  may  be  maintained  in  the  coil 
and  the  temperature  of  the  paraffin  raised  to  the  required  point. 


COST    OF    PARAFFINING    TUBS. 


The  question  of  the  cost  of  paraffining  tubs  will  doubtless  be 
brought  up  as  an  objection  to  this  method.  The  amount  of  paraffin 
necessary  to  coat  a  60-pound  tub  will  vary  with  the  method  of  apply- 
ing and  the  temperature  of  the  paraffin.  If  the  paraffin  is  hot  enough, 


PREVENTING  MOLDS  IN  BUTTER  TUBS.  13 

this  should  not  exceed  3  ounces  per  tub,  and  as  a  good  grade  of  par- 
affin may  be  purchased  at  about  8}  cents  a  pound  the  cost  will  be  less 
than  2  cents  per  tub.  But  even  this  small  sum  would  be  a  consider- 
able item  in  a  season's  run  and  would  be  a  serious  objection  in  some 
factories.  However,  there  is  another  factor  which  must  be  taken 
into  consideration.  In  an  ordinary  tub  the  loss  by  evaporation 
from  the  outside  and  by  absorption  of  water  from  the  butter  by  the 
tub  is  an  appreciable  quantity.  Coating  the  tub  with  paraffin  makes 
it  impervious  to  water,  and  this  loss  is  reduced  to  a  minimum. 

To  illustrate  this  point,  24  tubs  were  divided  into  two  lots  of  12  tubs 
each.  One  lot  was  paraffined  in  the  manner  previously  described, 
and  the  other  lot  was  soaked  overnight  with  cold  water  in  the  usual 
way.  The  tubs  were  weighed  before  filling  and  again  after  the  butter 
was  packed.  The  12  paraffined  tubs  contained  at  this  time  lbl\ 
pounds  of  butter  and  the  12  tubs  soaked  in  water  766J  pounds.  These 
tubs  were  all  filled  from  the  same  lot  of  butter,  were  held  in  the 
factory  refrigerator  three  days,  and  were  then  shipped  to  the  com- 
mission house,  where  they  were  weighed  on  the  eighth  day  after 
packing.  Each  tub  was  weighed  separately,  and  the  average  weight 
of  three  empty  tubs  was  taken  as  the  tare.  The  weight  of  butter 
obtained  in  this  way  was  for  the  paraffined  tubs  756  pounds,  a  loss  of 
\\  pounds;  for  the  soaked  tubs  759  pounds,  a  loss  of  7\  pounds.  In 
other  words,  by  the  use  of  about  15  cents'  worth  of  paraffin  the  price 
of  6  pounds  of  butter  was  saved.  In  butter  held  in  storage  for  any 
length  of  time  this  saving  would  undoubtedly  be  much  greater. 

It  should  be  remembered,  however,  that  paraffined  tubs  weigh  from 
1  to  2  pounds  less  than  tubs  prepared  in  the  ordinary  way,  and  unless 
the  tare  is  actually  determined  this  difference  will  be  lost  to  the 
butter  maker.  This  possibility  may  be  avoided  by  soaking  the  tubs 
before  paraffining.  To  do  this  it  is  necessary  to  keep  the  paraffin 
very  hot,  so  that  it  will  displace  the  water  in  the  pores  of  the  wood, 
or  the  soaked  tub  may  be  heated  on  a  steajn  jet  before  applying  the 
paraffin. 

The  labor  cost  of  paraffining  need  not  be  greater  than  in  the  usual 
method  of  soaking  tubs  in  cold  water  or  brine.  The  apparatus  needed 
as  here  illustrated  is  simple  and  inexpensive. 

SUMMARY. 

The  advantages  of  paraffining  may  be  summarized  as  follows: 

(1)  Certain  prevention  of  moldy  tubs. 

(2)  Prevention  of  mold  on  butter  and  liner  by  avoiding  air  space. 

(3)  Neater  appearance  of  tub. 

(4)  Reduction  of  loss  from  shrinkage. 

O 


UC  SOUTHERN  REGIONAL  LIBRARY  FACILITY 


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